A primary controller for use within a power converter, such as a switched mode power supply (SMPS), uses a low-voltage electrical power supply to function. This low-voltage electrical power may be supplied to a control voltage terminal of the primary controller from an auxiliary supply, which may comprise an auxiliary winding of a transformer and a rectifying diode. The primary controller may also include a monitor terminal configured to monitor a voltage of alternating current (AC) electrical power supplied to the primary controller. In some cases, the auxiliary supply may not be able to supply sufficient power to maintain the control voltage terminal at a voltage sufficient to enable the primary controller to function.